CN1978583A - Thermal interface material - Google Patents

Abstract

A thermal interface material, including base oil and filler powder, the base oil is pentaerythritol oleate, so that through the high lubricity of pentaerythritol oleate, sliding occurs between the fillers and the solid content of the filler is increased. Therefore, the thermal conductivity of the thermal interface material is improved, and the heat dissipation effect is improved.

Description

Thermal Interface Material

【Technical field】

The invention relates to a thermal interface material for heat dissipation of electronic components.

【Background technique】

With the continuous development of the electronic information industry, electronic products are moving toward thinner, smaller, multi-functional, and faster-running trends, and the heat released by electronic components is also increasing. As a result, its further development must face how to reduce the electronic The bottleneck of the working temperature of components. In order to make high-tech electronic products play their due functions, heat sinks and other heat dissipation components are generally installed on the electronic components to conduct away the heat generated by the electronic components when they are working, so as to ensure the stable operation of the electronic components.

However, if the heat dissipation element is directly placed on the electronic component, since the contact surface of the heat dissipation element and the electronic component is not completely flat, when the two are attached, the contact surface of the two cannot be fully contacted effectively and there is an air gap , and the thermal conductivity of air is very low, generally about 0.025W/(m·℃), which seriously affects the overall heat dissipation effect. Fill the air gap between the cooling element and the electronic component, reduce the interface thermal resistance, improve the heat dissipation effect, and ensure the normal operation of the electronic component.

Existing thermal interface materials are generally made of silicone oil (Silicone oil) as the base oil mixed with metal and metal oxide powders, so that the thermal interface material is in the form of a paste, which can be easily printed on radiators and other components, and through Metal or metal oxide powder meets the requirements of thermal conductivity, but limited by the nature of the silicone oil material itself, the proportion of metal or metal oxide in this thermal interface material is limited, and there are gaps between powders, which affect thermal conductivity , and as the operating speed of today's electronic products is getting higher and higher, it is necessary to provide a thermal interface material with better performance to reduce the interface thermal resistance between electronic components and heat dissipation components and ensure the safe operation of electronic components.

【Content of invention】

In view of this, it is necessary to provide a thermal interface material with improved performance.

The thermal interface material includes base oil and filler powder, and the base oil is pentaerythritol oleate.

Through the high lubricity of pentaerythritol oleate, the thermal interface material causes sliding between the fillers and increases the content of the filler, thereby improving the thermal conductivity of the thermal interface material and improving the heat dissipation effect.

【Detailed ways】

Below in conjunction with embodiment for further explanation.

The thermal interface material includes a base oil (Base Oil) and at least one filler powder (Filler). The filler powder is composed of powder with better thermal conductivity, the base oil is pentaerythritol oleate, and the solid content of the powder is increased by pentaerythritol oleate to form a thermal interface material with good thermal conductivity.

Pentaerythritol oleate is the reaction product of pentaerythritol and oleic acid. It is in the form of light yellow transparent liquid. , High lubricating oil base oil. The filler powder can be aluminum, zinc and other metals or their oxides. When pentaerythritol oleate is mixed with the filler powder to form the thermal interface material, the filler powder can provide the thermal interface material with good thermal conductivity, and use The high lubricity of pentaerythritol oleate causes relative sliding between the filler powders, thereby minimizing the gap between the powders, making the powders in close contact, and increasing the content of the filler powder in the thermal interface material , enhance the thermal conductivity of the thermal interface material.

As shown in Table 1, aluminum powder (Al), zinc oxide powder (ZnO) and their mixture are used as filler powders as examples to illustrate the performance of the thermal interface material.

Example 1 shows a thermal interface material formed with zinc oxide powder as a filler and pentaerythritol oleate. The masses of zinc oxide powder and base oil are 38.3112g and 11.6888g respectively, and the mass ratio of the two is about 330: 100. The average particle size of the zinc oxide powder is about 0.4 μm, which accounts for about 35% of the thermal interface material by volume, and the thermal resistance of this thermal interface material is about 0.252°C·cm ² /W.

Example 2 shows a thermal interface material formed by mixing aluminum powder as a filler with pentaerythritol oleate, in which the masses of aluminum powder and pentaerythritol oleate are 37.2928g and 12.7072g respectively, and the mass ratio of the two is about 300 : 100, the average particle size of aluminum powder is about 2.0 μm, and its volume ratio accounts for about 50% of the thermal interface material. The thermal resistance of this kind of thermal interface material is about 0.231°C·cm ² /W.

Example 3 reveals the thermal interface material formed by pentaerythritol oleate, aluminum powder and zinc oxide powder. The aluminum powder particles are relatively large, with an average particle size of about 2.0 μm, and the zinc oxide powder particles are small, with an average particle size of about 2.0 μm. is 0.4 μm, the quality of aluminum powder is 23.1476g, the quality of zinc oxide powder is less than the quality of aluminum powder, only 13.7171g, the quality of pentaerythritol oleate is 13.1353g, and its mass ratio with these two kinds of powder is about 100 :280, the volume ratio of the two powders to the thermal interface material is about 45%, and the thermal resistance of this thermal interface material is about 0.247°C·cm ² /W.

When the filler powder contains two or more powders, the selection of particle sizes of various powders is generally different, so that powders with small particle sizes can be filled between powders with large particle sizes, which can more effectively compensate for the gap between powders. Gap, increase the content of filler powder, as in Example 3, the particle size of zinc oxide powder is 0.4 μm, which is smaller than the particle size of aluminum powder (2.0 μm).

Table 1

Base oil (g) Filling (g) The volume occupied by the filler Thermal resistance Example one 11.6888 ZnO 38.3112 35% 0.252 Example two 12.7072 Al 37.2928 50% 0.231 Example three 13.1353 Al 23.1476 45% 0.247 ZnO 13.7171

When the particle size of the filler powder is smaller, the contact area between the powder and the powder is larger, the gap between the powder is smaller, and the thermal conductivity of the thermal interface material formed by it is better. Generally, the average particle size of the aluminum powder is selected. The diameter is 0.1-10 μm, and the average particle size of zinc oxide powder is generally between 0.1-5 μm. In order to achieve better thermal conductivity, powder with nanometer particle size can also be selected. As shown in Table 2, the filler also includes zinc oxide particles with a particle size of 50-70nm, wherein each group of data shows the mass ratio of various powders, such as base oil in group 1: Al: ZnO ( The mass ratio of 0.1-1.0 μm): ZnO (50-70 nm) is 1:1:2:1, and its thermal resistance is about 0.14-0.17 (°C·cm ² /W). It can be seen from Table 2 that the thermal resistance of the thermal interface material decreases significantly after adding nano-zinc oxide powder, and as the content of aluminum powder in the filler increases, the thermal resistance of the thermal interface material decreases accordingly.

Table 2

serial number base oil Filling (ratio) Thermal resistance (℃·cm ² /W) Al(0.1～10μm) ZnO(0.1～1.0μm) ZnO(50～70nm) 1 1 1 2 1 0.14～0.17 2 1 2 2 1 0.11～0.13 3 1 3 1 1 0.06～0.08

4 1 3 2 1 0.08～0.10 5 1 4 2 0 0.05～0.07 6 1 6 0 0 0.07～0.09

As mentioned above, the filler powder is used to provide the thermal conductivity of the thermal interface material, so the higher the content, the better the thermal conductivity of the thermal interface material. However, the powders need to be tightly bonded to reduce the gap between the powders, which is more beneficial The conduction of heat, correspondingly, the content of the base oil is limited. If the content of the base oil is too low, the thermal interface material cannot be made into a paste, so it is not convenient to print it on radiators and other components, which affects the thermal interface material. Thermal conductivity. Generally, the mass ratio of base oil to the thermal interface material is controlled below 25%. The preferred ratio of base oil to pentaerythritol oleate is between 1:5 and 1:12. The thermal interface formed by it The thermal conductivity of the material is better, its thermal conductivity is about 0.6-6.0 (W/m·K), and its thermal resistance is generally between 0.05-0.26 (°C·cm ² /W). Compared with the existing thermal interface material, its thermal resistance value is greatly reduced, and its thermal conductivity is greatly improved.

Claims (10)

1. a thermal interface material comprises base oil and weighting material powder, it is characterized in that: described base oil is a PETO.

2. thermal interface material as claimed in claim 1 is characterized in that: the quality of PETO accounts for the ratio of quality of this thermal interface material less than 25%.

3. thermal interface material as claimed in claim 1 is characterized in that: the mass ratio of PETO and weighting material powder is 1: 2.8～1: 12.

4. thermal interface material as claimed in claim 3 is characterized in that: the mass ratio of PETO and weighting material powder is 1: 5～1: 12.

5. as any described thermal interface material in the claim 1 to 4, it is characterized in that: this weighting material powder comprises metal or metal oxide powder.

6. thermal interface material as claimed in claim 5 is characterized in that: this weighting material powder be aluminium powder and Zinc oxide powder at least one of them.

7. thermal interface material as claimed in claim 5 is characterized in that: this weighting material powder comprises aluminium powder, and the median size of described aluminium powder is 0.1～10 μ m.

8. thermal interface material as claimed in claim 5 is characterized in that: this weighting material powder comprises Zinc oxide powder, and the median size of described Zinc oxide powder is 0.1～5 μ m.

9. thermal interface material as claimed in claim 5 is characterized in that: this weighting material powder comprises Zinc oxide powder, and described Zinc oxide powder is a nano particle.

10. thermal interface material as claimed in claim 9 is characterized in that: the particle diameter of Zinc oxide powder is 50nm～70nm.